#define  _CRT_SECURE_NO_WARNINGS
#include <vector>
using namespace std;

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int n = nums.size();
        int left = 0, right = n - 1;

        while (left <= right)
        {
            int mid = left + (right - left) / 2;
            if (nums[mid] > target)
                right = mid - 1;
            else if (nums[mid] < target)
                left = mid + 1;
            else
                return mid;
        }
        return -1;
    }
};